Tanzania, East African country situated just south of the Equator. Tanzania was formed as a sovereign state in 1964 through the union of the theretofore separate states of Tanganyika and Zanzibar. Mainland Tanganyika covers more than 99 percent of the combined territories’ total area. Mafia Island is administered from the mainland, while Zanzibar and Pemba islands have a separate government administration. Dodoma, since 1974 the designated official capital of Tanzania, is centrally located on the mainland. Dar es Salaam, however, remains the seat of most government administration, as well as being the largest city and port in the country.

Ol Doinyo LengaiRobert Francis/Robert Harding Picture LibraryHighlands associated with the Western Rift Valley are formed by the Ufipa Plateau, the Mbeya Range, and Rungwe Mountain in the southwestern corner of the country. From there the southern highlands run northeastward along the Great Rift to the Ukuguru and Nguru mountains northwest of Morogoro. Extending from the northern coast, the Usambara and Pare mountain chains run in a southeast-to-northwest direction, culminating in Kilimanjaro’s lofty snow-clad peak and continuing beyond to Mount Meru (14,978 feet [4,565 metres]). Immediately to the west of Mount Meru, another chain of mountains begins, which includes the still-active volcano Ol Doinyo Lengai and the Ngorongoro Crater, the world’s largest caldera, or volcanic depression. This chain extends through a corridor between Lake Eyasi and Lake Manyara toward Dodoma.

Drainage

Victoria, LakeK. Muller/DeA Picture LibraryBecause of its numerous lakes, approximately 22,800 square miles (59,000 square km) of Tanzania’s territory consists of inland water. Lake Victoria, which ranks as the world’s second largest freshwater lake, is not part of the Rift System. Although Tanzania has no big rivers, it forms the divide from which the three great rivers of the African continent rise—the Nile, the Congo, and the Zambezi, which flow to the Mediterranean Sea, the Atlantic Ocean, and the Indian Ocean, respectively. Separated by the central plateau, the watersheds of these rivers do not meet.

All of Tanzania’s major rivers—the Ruvuma, the Rufiji, the Wami, and the Pangani—drain into the Indian Ocean. The largest, the Rufiji River, has a drainage system that extends over most of southern mainland Tanzania. The Kagera River flows into Lake Victoria, whereas other minor rivers flow into internal basins formed by the Great Rift Valley. With so many rivers, mainland Tanzania is rich in hydroelectricity potential.

Soils

The variety of soils in mainland Tanzania surpasses that of any other country in Africa. The reddish brown soils of volcanic origin in the highland areas are the most fertile. Many river basins also have fertile soils, but they are subject to flooding and require drainage control. The red and yellow tropical loams of the interior plateaus, on the other hand, are of moderate-to-poor fertility. In these regions, high temperatures and low rainfall encourage rapid rates of oxidation, which result in a low humus content in the soil and, consequently, a clayey texture rather than the desired crumblike structure of temperate soils. Also, tropical downpours, often short in duration but very intense, compact the soil; this causes drainage problems and leaches the soil of nutrients.

Climate

Mainland Tanzania can be divided into four principal climactic and topographic areas: the hot and humid coastal lowlands of the Indian Ocean shoreline, the hot and arid zone of the broad central plateau, the high inland mountain and lake region of the northern border, where Mount Kilimanjaro is situated, and the highlands of the northeast and southwest, the climates of which range from tropical to temperate. Tanzania’s warm equatorial climate is modified by variations in elevation. The high amount of solar radiation throughout the year is associated with a limited seasonal fluctuation of temperature: the mean monthly variation is less than 9 °F (5 °C) at most stations. Ground frosts rarely occur below 8,200 feet (2,500 metres).

Rainfall is highly seasonal, being influenced greatly by the annual migration of the intertropical convergence zone. Roughly half of mainland Tanzania receives less than 30 inches (750 mm) of precipitation annually, an amount considered to be the minimum required for most forms of crop cultivation in the tropics. The central plateau, which receives less than 20 inches (510 mm) per year on average, is the driest area and experiences a single rainy season between December and May. Precipitation is heavier on the coast, where there are two peaks of precipitation: October–November and April–May. The offshore islands and many highland areas have high annual precipitation totals of more than 60 inches (1,520 mm).

1Includes 107 indirectly elected seats (102 for women, 5 for Zanzibar [including 2 for women]), 10 seats appointed by the President (including 5 for women), and a seat for the Attorney General serving ex officio.

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